JPH04235941A - Process for acylating naphthyl ether with zeolite catalyst - Google Patents

Abstract

PURPOSE: To prepare the compounds useful as intermediates for the syntheses of pharmaceuticals and monomers for polyester by acylating readily naphthyl ethers, using zeolite-type catalyst, in a medium which is not corrosive and toxic, and also without solvent.

CONSTITUTION: The acylated naphthyl ethers of formula I (R¹, R² are each 1-10C alkyl, 2-10C alkenyl or 3-8C cycloalkyl, R² is additionally 6-10C aryl) are prepared by the reaction of naphthyl ethers of formula II with acylating agent of formula, R²-CO-X (X is Cl, Br, -OCOR², OH, etc.) at 30-500°C using zeolite-type catalyst of formula, Z.Al₂O₃.xSiO₂ [Z is M'₂O, M"O, etc., (M' is alkaline metals, ammonium or H; M" is alkaline earth metals); x is 4-4,000]. The catalyst is preferably formed from tetrahedron having at least 10 pores and preferably, the zeolite is replaced by other metal ions having at least 50% of the negative lattice charges (e.g. proton. ammonium).

COPYRIGHT: (C)1992,JPO

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for acylating naphthyl ethers using a zeolite catalyst. The product, especially 2-acetyl-6-methoxynaphthalene, is
It is an important intermediate in the production of monomers for pharmaceuticals and polyesters.

0002

BACKGROUND OF THE INVENTION It is known to acylate naphthyl ethers, such as methoxynaphthalene, using Lewis acids, such as AlCl3, as catalysts. In this method, 1-naphthyl ether is acylated at the 4-position, but when using 2-naphthyl ethers, the position of acylation is strongly dependent on the choice of solvent, and the reaction can be controlled, e.g. When carried out in carbon, 1-acyl-2-alkoxynaphthalene is the main product. On the other hand, if the reaction is carried out for example in nitrobenzene, 6-acyl-2-alkoxynaphthalenes are formed (Houben-We
yl, Methoden der Organis
chen Chemie 4th edition, Volume VII/2a,
pp. 71-73 (1973)).

2-Naphthyl ethers can be reacted with high selectivity in anhydrous hydrofluoric acid to give products acylated at the 6-position (US Pat. No. 4,593,125). .

However, these methods have a number of drawbacks. Therefore, Lewis acid catalysts must be utilized in at least stoichiometric amounts to carry out the acylation reaction. During work-up of the reaction product, the catalyst is destroyed and inorganic salts are formed. In any case, this reaction must be carried out using a solvent. In the case of acylation in hydrofluoric anhydride, the catalyst is at the same time the solvent. After separation from the reaction products, the hydrofluoric acid can be reused. The acylated product must be neutralized and the salt obtained in the same way. Furthermore, hydrofluoric anhydride is highly toxic and corrosive. Processing with hydrofluoric anhydride requires industrially expensive equipment made of special materials.

[0005]

Accordingly, improved naphthyl ethers are distinguished in that they are particularly easy to manipulate and can be carried out in non-corrosive and/or toxic media and without solvents. There is a need for an acylation method.

[0006]

[Means for solving the problem] Formula

[0007]

The naphthyl ether represented by the formula Z.Al2O3.xSiO2 (II
I) [wherein, Z is M I2 O, MIIO and/or (MIII)2 O3 (wherein M I is an alkali metal atom, ammonium or hydrogen atom, and M I
is an alkaline earth metal atom, and MIII is a rare earth metal atom with an atom number of 57 to 71 in the Periodic Table of the Elements, and x is a number of 4 to 4000). By at least 5
0% negative lattice charge on protons, ammonium and/or
or other metal ions described in MII and MIII, and an acylating agent of the formula R2-CO-X with the proviso that its pores are formed from at least 10 tetrahedral atoms. React with the formula

[0008]

[Image Omitted] (In the formula, R1 and R2 are independently C1 to C
10-alkyl, C2-C10-alkenyl or C
3-C8-cycloalkyl, and R2 is additionally a C6-C10-aryl group, and X
is Cl, Br, -OCOR2, OH or C1 to C
It has been found that it is possible to obtain acylated naphthyl ethers represented by the following formula: 3-alkoxy group.

Phenyl ethers, such as anisole, can be acylated using zeolites as catalysts, and it is possible to achieve conversions of more than 75% and selectivities of 98% to 100% with respect to 4-alkoxyphenyl ketones. is clearly known (German Patent Publication No. 3)
, No. 809, 260). Nevertheless, according to the prior art, it was unexpected that so many bulky naphthyl ethers compared to phenyl ethers could be acylated using zeolites as catalysts. Weisz (Pure Appl. Che
m. 52, 2091-2130 (1980), only if the dimensions of the two molecules do not differ significantly in the range of configurational dispersion (i.e., the width of the diffusing molecule and the pore have comparable dimensions). The diffusion coefficients of two molecules can differ by large orders of magnitude (eg, the effective diffusion coefficients of o- and p-xylene in zeolite ZSM-5 differ by an order of 104, Weisz, supra). The dispersion coefficient is temperature dependent. This dependence can be explained by a formula similar to Arenuse's formula. In this case, the activation energies for dispersion are all increased, and the molecular dimensions and pore widths become more consistent (Weisz, supra). This finding indicates that bulky naphthyl ethers and still bulky acylated reaction products diffuse into zeolites quickly enough and only at very high temperatures to obtain satisfactory conversions and yields. It was expected that it would not be able to diffuse into the pores.

Surprisingly, however, naphthyl ethers can already react even at low temperatures. Thus, for example, reaction of 2-methoxynaphthalene with acetic anhydride at 120° C. in the liquid phase gives acetylmethoxynaphthalenes with a selectivity of 98% and a yield of 20%.

Additionally, when using 2-naphthyl ethers, two types of products are produced in principle, namely 2-naphthyl ether acetylated in the 1- or 6-position, We have found that this can be varied by varying the experimental conditions and the naphthylating agent. Therefore, acylation occurs predominantly at the 1-position when acidic chlorides are used in the reaction, and at the 6-position when a carboxylic acid/carboxylic acid anhydride mixture is used. This acylation reaction can be carried out both in the gas phase and in the liquid phase. Liquid phase reactions are preferred in this case. When operating in the liquid phase, the proportion of naphthyl ether acylated in the 6-position increases if the acetylating agent is slowly converted and no reaction mixture is present from the beginning. The results of this different reaction variant are:
Included in the Examples.

When operating in the gas phase, the reaction temperature increases and the formation of 6-acetyl-2-alkoxynaphthalene increases. Some results for this are also included in the Examples.

This reaction proceeds very selectively in the liquid phase. On the other hand, in the gas phase, isomerization of alkoxynaphthalenes to alkylnaphthols, hydrolysis of heterogenized reactants of alkoxynaphthalenes, and formation of naphthyl ethers occur to some extent. At higher temperatures, reaction of carboxylic acid derivatives occurs in a gas phase reaction.

Examples of suitable R1 and R2 residues include methyl, ethyl, propyl, isopropyl, butyl,
isobutyl, amyl isomers, hexyl isomers, octyl isomers, nonyl isomers, decyl isomers and vinyl, propenyl, butenyl, amylene isomers, hexane isomers, octane isomers and decene isomers.

Examples of specific naphthyl ethers (I) for the process according to the invention are 1- and 2-methoxynaphthalene, 1- and 2-ethoxynaphthalene, 1- and 2-propoxynaphthalene, cyclohexyl 1-
naphthyl ether and cyclohexyl 2-naphthyl ether.

Examples of acylating agents for the process according to the invention are acetic acid, acetic anhydride, acetyl chloride, acetyl bromide, methyl acetate, propionic acid, propionic anhydride, butyric acid, butyric anhydride, propionyl chloride, butyryl chloride. , isobutyric acid, isobutyric anhydride,
Mention may be made of isobutyryl chloride, pivaloyl chloride, pivalic acid, valeric acid, valeryl chloride and/or valeric anhydride. Carboxylic anhydrides or mixtures of carboxylic acids and mixtures thereof are preferred in the present invention.

Catalysts suitable for the process according to the invention are:
It is a zeolite defined by formula (III) whose pores are composed of at least 10 tetrahedrons. Si and Al are defined as tetrahedra surrounded by oxygen in a tetrahedral structure. These tetrahedra combine with a common oxygen atom and form a crystal structure penetrated by defined pores and vacancies. The width and shape of the pores depends on the type of zeolite (e.g. Atlas of
Zeolite Structure Types
, W. M. Meier and D. H.
(see Olson, 1987).

However, also suitable are zeolites in which part of the aluminum and silicon is replaced by other lattice atoms, preferably boron, iron, gallium, germanium, titanium and/or zirconium atoms.

The negative charge of the AlO-4 tetrahedron is replaced by exchangeable cations such as H+, Na+, K+,
Ca2+, Mg2+ or organic cations such as N+
Consumed by R4.

Zeolites suitable for the process according to the invention are:
For example, zeolite ZSM-5 (U.S. Pat. No. 3,702,
No. 886), ZSM-11 (U.S. Pat. No. 3,70
9,979), ZSM-12 (U.S. Patent No. 3,
No. 970,544), ZSM-20 (U.S. Pat. No. 3,972,983), Beta (U.S. Pat.
, 308,069), EU-1 (European Patent No. 042,266), Y, L, offretite or mordenite (D.W. Breck, “Zeol
ite Molecular Sieves”,1
(described in 974).

[0021] Some of the tetrahedral atoms are, for example, Si, Co,
Molecular sieves based on aluminum phosphate substituted with Mg and/or Mn can be used.

The zeolites mentioned above can be produced by hydrothermal synthesis according to the method from the above mentioned literature. After crystallization, the zeolite is filtered off, dried and the organic template is removed from the pores under an oxidizing atmosphere, preferably in air.
Calcinate to remove. (Template - Free (
The template-free form is the form without alkylammonium or phosphonium and amine. ) The alkali metal ions that may be present (in this case Z in formula (III) is M2O) are then replaced by ion exchange with divalent or trivalent ions of alkaline earth metals or rare earth metals or with ammonium ions or Exchange with protons. NH4+ or H+
Ion exchange by is very particularly preferred according to the invention. This acidic modification is necessary so that the zeolite exhibits no other catalytic activity. In the present invention it is advantageous to replace at least 50%, preferably at least 75%, of the alkali metal salts by other ions mentioned above. At 200 to 800°C, preferably 400 to 550°C, the zeolite is also converted to the catalytically active form by dehydration (and in the case of NH4 + by deammonium). The SiO3 /Al2 O3 ratio of the zeolite described above depends on the type of zeolite, but can range over a wide range, for example from 4 to 4000. The aluminum content of the zeolites used according to the invention is reduced within the ranges mentioned above by treatment with mineral acids, organic acids or chelating substances for the purpose of continuing the modification. 20 to 300 S
The iO3/Al2O3 ratio is preferred. The crystallite size is, for example, about 0.01 to about .mu.m, preferably about 0.01 to about .mu.m.
0.05 to 0.1 μm.

For use according to the invention, the zeolites are advantageously brought into extruded form with a suitable application form, for example with a binder. A suitable binder is
In particular oxides, hydroxides of aluminum and oxides of silicon, titanium and zirconium and clay materials.

The acetylating agent is used in an amount of, for example, 0.1 to 20 mol, preferably 0.5 mol, per mol of naphthyl ether.
It can be used in ratios from 5 to 5 moles. The reaction temperature is approximately 30
The temperature is from 100 to 500°C, preferably from 100 to 300°C. In the present invention, it is preferred to select lower temperatures of about 30 to 200°C, preferably 120 to 170°C, for liquid phase reactions, and about 150 to about 500°C, preferably about 100°C, for gas phase reactions. 20
Preference is given to using an elevated temperature range of 0 to 300°C.

Pressure has little effect on the progress of the reaction. The pressure can be adjusted to values of 0.5 to 100 bar, preferably 1 to 10 bar. Most conveniently, the reaction is carried out at atmospheric pressure. For reactions in the liquid phase, it is necessary to operate under pressure in order to achieve a reaction temperature above the boiling point of the reaction mixture.

The acylation in the liquid phase is carried out in all suitable apparatus, most simply in stirred vessels using ground suspended catalysts.

The reactants together with the catalyst are brought to the reaction temperature in this case. In certain cases it is more preferred to add one of the reaction components, preferably the acetylating agent, slowly after reaching the reaction temperature. This reaction is carried out in the absence or presence of a solvent inert to the reactants and catalyst, such as nitrobenzene.

It is preferred to use from 0.5 to 100% by weight of catalyst, preferably from about 1 to 10% by weight, based on the weight of the reactants used. The reaction time is approximately 0.5
The duration ranges from hours to several days, preferably about 2 to 10 hours. After carrying out the reaction in the liquid phase, the zeolite can be removed from the reaction mixture in a simple manner by filtration.

In principle, all equipment suitable for gas phase reactions can be used to carry out the reaction in the gas phase. Solid bed fluidized reactors are the simplest to operate industrially. In this case, the catalyst is introduced in the form of pellets. To prepare pellets, zeolites are compressed together with Al2O3 or SiO3 or in binder-free form.

The reactants can be metered into the reaction vessel in liquid form; naphthyl ether, which is solid at room temperature, can be metered or dissolved in an inert solvent or in an excess of acetylating agent. When operating in the gas phase with washing, the reactants are evaporated upstream of the catalyst bed. The reactants can also be converted to the gas phase by suitable equipment upstream of the reaction vessel and then passed over the catalyst. In this case, the above reactants are used as they are or mixed with a gas inert to the reaction. The product is condensed downstream of the reactor.

The residence time of the reactants is about 0.05 to 2
0 seconds, preferably 1 to 10 seconds. Space velocity (L
HSV=liquid hourly space velocity) is in the range from 0.1 to 5 h-1, advantageously in the range from 0.5 to 2 h-1.

The mixture obtained in the reaction can be separated by a conventional method. Unreacted substances are distilled off and used again in the acylation reaction. The resulting acylated product isomer is
They are generally separated coarsely by distillation, and these can be purified to the desired degree by further purification steps, such as distillation and recrystallization.

[0033]

EXAMPLES The following examples are intended to explain the method according to the invention in more detail, but are not intended to be limiting.

EXAMPLES Catalysis experiments in the liquid phase were carried out in a stirred vessel. The zeolite was utilized in powder form and was heated under reduced pressure for 25 minutes before the reaction.
It was dried at 0°C for 1 hour. Reactants are Examples 13 and 1
The components other than 4 were used at equimolar ratios. Some results for liquid phase acylation of 2-methoxynaphthalene (2-MO-Np) are summarized in Table 1.

Gas phase experiments were carried out in a solid bed fluidized reactor under atmospheric pressure. 2-methoxynaphthalene is dissolved in excess acylating agent and the reaction mixture is metered in liquid form;
Evaporated upstream of the catalyst bed. Nitrogen gas was used as the carrier gas. After various catalyst passage times the products were condensed downstream of the reactor and analyzed by gas chromatography. The catalyst was utilized in the form of an extrudate containing 21% by weight of SiO2 as binder. Some results are listed in Table 2.

[0036]

[Table 1] a) Crystal size 0.05μm b) Crystal size
0.05 μm c) Ac=CH3 CO d) Based only on the product from 2-MO-Np e) Amount ratio of 2-MO-Np: Ac2 O = 1:0.5f
)2-MO-Np:Ac2O quantitative ratio = 1:3

003
7]

Table 2: a) Ac=CH3CO b) Based only on products from 2-MO-Np

Claims (15)

[Claims] Claim 1: An acylating agent represented by the formula R2 -CO-X is used to form a compound of the formula [Formula 1] (wherein R1 and R2 are independently C1 to C
10-alkyl, C2-C10-alkenyl or C
3-C8-cycloalkyl, and R2 is additionally a C6-C10-aryl group, and X
is Cl, Br, -OCOR2, OH or C1 to C
A method for acylating naphthyl ether represented by the formula [Chemical formula 2] to obtain an acylated naphthyl ether represented by [3-alkoxy group], the method comprising:
Anhydrous or template-f
ree) form with the formula Z・Al2O3・xSiO2 (I
II) [wherein, Z is M I2 O, MIIO and/or (MIII)2 O3 (where M I is an alkali metal atom, ammonium or hydrogen atom, and M I
I is an alkaline earth metal atom, and MIII is a rare earth metal atom with an atom number of 57 to 71 in the Periodic Table of the Elements, and x is a number of 4 to 4000). Below, at least 50% negative lattice charge is present on protons, ammonium and/or MII
and other metal ions mentioned in MIII and carrying out the reaction under the conditions that the pores are formed from at least 10 tetrahedral atoms. 2. When Z is M2O, at least 75% of the alkali metal atoms are hydrogen atoms, ammonium,
2. The method of claim 1, wherein the substitution is with alkaline earth metal atoms and/or rare earth metal atoms. [Claim 3] x in formula (III) is 20 to 30
4. The method according to claim 2 or 3, wherein 0. [Claim 4] The crystallite size of the zeolite is about 0.0.
1 to about 10 μm, preferably about 0.05 to about 0
．． 4. The method of one or more of claims 1 to 3, wherein the diameter is 1 μm. 5. A process according to claim 1, wherein the reaction is carried out at a temperature of from about 30 to about 500°C, preferably from about 100 to about 300°C. 6. The method according to claim 1, wherein the reaction is carried out in liquid phase. 7. The method of claim 6, wherein the reaction is carried out at a temperature of about 30 to about 200°C, preferably about 120 to about 170°C. 8. The method according to claim 1, wherein the reaction is carried out in the gas phase. 9. The method of claim 8, wherein the reaction is carried out at a temperature of about 150 to about 500°C, preferably about 200 to about 300°C. 10. The reaction is carried out at 0.5 to 100 bar,
10. A process according to one or more of claims 1 to 9, preferably carried out in a pressure range of 1 to 10 bar. Claim 11: Per mole of naphthyl ether, 0
．． 11. Process according to one or more of claims 1 to 10, characterized in that from 1 to 20 mol, preferably from 0.5 to 5 mol, of acetylating agent is used. 12. The process as claimed in claim 1, wherein a carboxylic acid anhydride or a mixture of carboxylic acid and its anhydride is used as the acetylating agent. 13. A process according to claim 1, wherein 2-naphthyl ether, in particular 2-methoxynaphthalene, is acetylated. 14. 0 relative to the weight of reactants used
．． 5 to 100% by weight of catalyst, preferably 1 to 1
14. A method according to one or more of claims 1 to 13, wherein 0% by weight of catalyst is used. 15. The acetylating agent is added slowly to the naphthyl ether/catalyst suspension at the reaction temperature.
7 and one or more of the methods of 10-14.